Create stats_buffer_writer

Move iovec* construction and noteLogLoss from stats_event_list to
stats_buffer_writer.h.
Expose write_buffer_to_statsd that takes in a byte array and writes
it to the statsd socket. Currently exposed for StatsLog.write JNI call.

This change also allows getting rid of stats_event_list once all clients
have migrated to stats_event

Bug: 145619049
Test: m -j libstatssocket
Change-Id: I0048e392c2f5039eb70dacf4e91a43d3f32e8749

libstats/socket/Android.bp

@@ -20,7 +20,10 @@
 cc_library {
     name: "libstatssocket",
     srcs: [
+        "stats_buffer_writer.c",
         "stats_event.c",
+        // TODO(b/145573568): Remove stats_event_list once stats_event
+        // migration is complete.
         "stats_event_list.c",
         "statsd_writer.c",
     ],

libstats/socket/include/stats_buffer_writer.h

@@ -0,0 +1,29 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <stddef.h>
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif  // __CPLUSPLUS
+void stats_log_close();
+int write_buffer_to_statsd(void* buffer, size_t size, uint32_t atomId);
+#ifdef __cplusplus
+}
+#endif  // __CPLUSPLUS

libstats/socket/include/stats_event.h

@@ -76,7 +76,7 @@
 
 #ifdef __cplusplus
 extern "C" {
-#endif
+#endif  // __CPLUSPLUS
 
 struct stats_event;
 
@@ -132,6 +132,6 @@ uint32_t stats_event_get_errors(struct stats_event* event);
 
 #ifdef __cplusplus
 }
-#endif
+#endif  // __CPLUSPLUS
 
 #endif  // ANDROID_STATS_LOG_STATS_EVENT_H

libstats/socket/include/stats_event_list.h

@@ -24,11 +24,9 @@ extern "C" {
 #endif
 void reset_log_context(android_log_context ctx);
 int write_to_logger(android_log_context context, log_id_t id);
-void note_log_drop(int error, int atom_tag);
+void note_log_drop(int error, int atomId);
 void stats_log_close();
 int android_log_write_char_array(android_log_context ctx, const char* value, size_t len);
-extern int (*write_to_statsd)(struct iovec* vec, size_t nr);
-
 #ifdef __cplusplus
 }
 #endif

libstats/socket/stats_buffer_writer.c

@@ -0,0 +1,130 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "include/stats_buffer_writer.h"
+#ifdef __ANDROID__
+#include <cutils/properties.h>
+#endif
+#include <errno.h>
+#include <sys/time.h>
+#include <sys/uio.h>
+#include "statsd_writer.h"
+
+static const uint32_t kStatsEventTag = 1937006964;
+
+extern struct android_log_transport_write statsdLoggerWrite;
+
+static int __write_to_statsd_init(struct iovec* vec, size_t nr);
+static int (*__write_to_statsd)(struct iovec* vec, size_t nr) = __write_to_statsd_init;
+
+void note_log_drop(int error, int atomId) {
+    statsdLoggerWrite.noteDrop(error, atomId);
+}
+
+void stats_log_close() {
+    statsd_writer_init_lock();
+    __write_to_statsd = __write_to_statsd_init;
+    if (statsdLoggerWrite.close) {
+        (*statsdLoggerWrite.close)();
+    }
+    statsd_writer_init_unlock();
+}
+
+int write_buffer_to_statsd(void* buffer, size_t size, uint32_t atomId) {
+    int ret = 1;
+
+#ifdef __ANDROID__
+    bool statsdEnabled = property_get_bool("ro.statsd.enable", true);
+#else
+    bool statsdEnabled = false;
+#endif
+
+    if (statsdEnabled) {
+        struct iovec vecs[2];
+        vecs[0].iov_base = (void*)&kStatsEventTag;
+        vecs[0].iov_len = sizeof(kStatsEventTag);
+        vecs[1].iov_base = buffer;
+        vecs[1].iov_len = size;
+
+        ret = __write_to_statsd(vecs, 2);
+
+        if (ret < 0) {
+            note_log_drop(ret, atomId);
+        }
+    }
+
+    return ret;
+}
+
+static int __write_to_stats_daemon(struct iovec* vec, size_t nr) {
+    int save_errno;
+    struct timespec ts;
+    size_t len, i;
+
+    for (len = i = 0; i < nr; ++i) {
+        len += vec[i].iov_len;
+    }
+    if (!len) {
+        return -EINVAL;
+    }
+
+    save_errno = errno;
+#if defined(__ANDROID__)
+    clock_gettime(CLOCK_REALTIME, &ts);
+#else
+    struct timeval tv;
+    gettimeofday(&tv, NULL);
+    ts.tv_sec = tv.tv_sec;
+    ts.tv_nsec = tv.tv_usec * 1000;
+#endif
+
+    int ret = (int)(*statsdLoggerWrite.write)(&ts, vec, nr);
+    errno = save_errno;
+    return ret;
+}
+
+static int __write_to_statsd_initialize_locked() {
+    if (!statsdLoggerWrite.open || ((*statsdLoggerWrite.open)() < 0)) {
+        if (statsdLoggerWrite.close) {
+            (*statsdLoggerWrite.close)();
+            return -ENODEV;
+        }
+    }
+    return 1;
+}
+
+static int __write_to_statsd_init(struct iovec* vec, size_t nr) {
+    int ret, save_errno = errno;
+
+    statsd_writer_init_lock();
+
+    if (__write_to_statsd == __write_to_statsd_init) {
+        ret = __write_to_statsd_initialize_locked();
+        if (ret < 0) {
+            statsd_writer_init_unlock();
+            errno = save_errno;
+            return ret;
+        }
+
+        __write_to_statsd = __write_to_stats_daemon;
+    }
+
+    statsd_writer_init_unlock();
+
+    ret = __write_to_statsd(vec, nr);
+    errno = save_errno;
+    return ret;
+}

libstats/socket/stats_event.c

@@ -18,7 +18,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <time.h>
-#include "include/stats_event_list.h"
+#include "stats_buffer_writer.h"
 
 #define STATS_EVENT_TAG 1937006964
 #define LOGGER_ENTRY_MAX_PAYLOAD 4068
@@ -323,11 +323,5 @@ void stats_event_build(struct stats_event* event) {
 void stats_event_write(struct stats_event* event) {
     stats_event_build(event);
 
-    // Prepare iovecs for write to statsd.
-    struct iovec vecs[2];
-    vecs[0].iov_base = &event->tag;
-    vecs[0].iov_len = sizeof(event->tag);
-    vecs[1].iov_base = &event->buf;
-    vecs[1].iov_len = event->size;
-    write_to_statsd(vecs, 2);
+    write_buffer_to_statsd(&event->buf, event->size, event->atomId);
 }

libstats/socket/stats_event_list.c

@@ -18,7 +18,7 @@
 
 #include <string.h>
 #include <sys/time.h>
-#include "statsd_writer.h"
+#include "stats_buffer_writer.h"
 
 #define MAX_EVENT_PAYLOAD (LOGGER_ENTRY_MAX_PAYLOAD - sizeof(int32_t))
 
@@ -38,11 +38,6 @@ typedef struct {
     uint8_t storage[LOGGER_ENTRY_MAX_PAYLOAD];
 } android_log_context_internal;
 
-extern struct android_log_transport_write statsdLoggerWrite;
-
-static int __write_to_statsd_init(struct iovec* vec, size_t nr);
-int (*write_to_statsd)(struct iovec* vec, size_t nr) = __write_to_statsd_init;
-
 // Similar to create_android_logger(), but instead of allocation a new buffer,
 // this function resets the buffer for resuse.
 void reset_log_context(android_log_context ctx) {
@@ -92,12 +87,7 @@ int stats_write_list(android_log_context ctx) {
         msg += sizeof(uint8_t) + sizeof(uint8_t);
     }
 
-    struct iovec vec[2];
-    vec[0].iov_base = &context->tag;
-    vec[0].iov_len = sizeof(context->tag);
-    vec[1].iov_base = (void*)msg;
-    vec[1].iov_len = len;
-    return write_to_statsd(vec, 2);
+    return write_buffer_to_statsd((void*)msg, len, 0);
 }
 
 int write_to_logger(android_log_context ctx, log_id_t id) {
@@ -120,80 +110,6 @@ int write_to_logger(android_log_context ctx, log_id_t id) {
     return retValue;
 }
 
-void note_log_drop(int error, int tag) {
-    statsdLoggerWrite.noteDrop(error, tag);
-}
-
-void stats_log_close() {
-    statsd_writer_init_lock();
-    write_to_statsd = __write_to_statsd_init;
-    if (statsdLoggerWrite.close) {
-        (*statsdLoggerWrite.close)();
-    }
-    statsd_writer_init_unlock();
-}
-
-/* log_init_lock assumed */
-static int __write_to_statsd_initialize_locked() {
-    if (!statsdLoggerWrite.open || ((*statsdLoggerWrite.open)() < 0)) {
-        if (statsdLoggerWrite.close) {
-            (*statsdLoggerWrite.close)();
-            return -ENODEV;
-        }
-    }
-    return 1;
-}
-
-static int __write_to_stats_daemon(struct iovec* vec, size_t nr) {
-    int save_errno;
-    struct timespec ts;
-    size_t len, i;
-
-    for (len = i = 0; i < nr; ++i) {
-        len += vec[i].iov_len;
-    }
-    if (!len) {
-        return -EINVAL;
-    }
-
-    save_errno = errno;
-#if defined(__ANDROID__)
-    clock_gettime(CLOCK_REALTIME, &ts);
-#else
-    struct timeval tv;
-    gettimeofday(&tv, NULL);
-    ts.tv_sec = tv.tv_sec;
-    ts.tv_nsec = tv.tv_usec * 1000;
-#endif
-
-    int ret = (int)(*statsdLoggerWrite.write)(&ts, vec, nr);
-    errno = save_errno;
-    return ret;
-}
-
-static int __write_to_statsd_init(struct iovec* vec, size_t nr) {
-    int ret, save_errno = errno;
-
-    statsd_writer_init_lock();
-
-    if (write_to_statsd == __write_to_statsd_init) {
-        ret = __write_to_statsd_initialize_locked();
-        if (ret < 0) {
-            statsd_writer_init_unlock();
-            errno = save_errno;
-            return ret;
-        }
-
-        write_to_statsd = __write_to_stats_daemon;
-    }
-
-    statsd_writer_init_unlock();
-
-    ret = write_to_statsd(vec, nr);
-    errno = save_errno;
-    return ret;
-}
-
 static inline void copy4LE(uint8_t* buf, uint32_t val) {
     buf[0] = val & 0xFF;
     buf[1] = (val >> 8) & 0xFF;